Rhythm IgG (Recombinant) Antibody Test (Serum/Plasma)
This test checks for the presence of antibodies against the Rh (D) blood group antigen in your blood. These antibodies can develop after exposure to Rh-positive blood (e.g., during pregnancy or blood transfusions) and may affect future pregnancies or blood transfusions.
["Helps determine if you have Rh antibodies that could impact future pregnancies or blood safety."]
Key facts at a glance
- LOINC
- 1313-6
- Short code
- Rh Ig Vials Recom Patient
- Synonyms
- Rh Ig Vials Recom Patient
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Doctors may order this test if you’ve had a pregnancy with Rh-positive fetal blood (e.g., miscarriage, stillbirth, or delivery), a blood transfusion, or if you’re at risk for Rh sensitization. It’s also used to screen pregnant women who are Rh-negative to prevent complications like hemolytic disease of the fetus or newborn (HDFN).
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw blood. The process takes about 5 minutes, and you may feel a brief pinch. If you’re pregnant, your healthcare provider will discuss the timing with you based on your medical history.
What the Test Results Mean
If antibodies are found, they’ll be measured to determine their level. High levels may indicate an ongoing immune response that could affect future pregnancies or blood compatibility. Your doctor will interpret results in the context of your medical history and symptoms.
Potential Risks and Considerations
The most common risk is a mild bruise or slight discomfort at the injection site. Rarely, blood tests can cause allergic reactions or infections. If you’re pregnant, your doctor will monitor you closely to prevent complications like preterm labor or fetal anemia.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Rh IgG Antibody Screen
Frequently asked questions
If antibodies are detected, it means your immune system has recognized Rh-positive blood as foreign. This can lead to complications such as hemolytic anemia in newborns if exposed during pregnancy or delivery. Early detection helps guide management, such as Rh immune globulin (RhIG) administration during pregnancy to prevent sensitization.
Yes, the test is performed on serum or plasma, the liquid part of your blood that contains antibodies. The method used is an immunoassay to detect Rh IgG antibodies.
If your results are positive, your doctor may recommend further testing or monitoring, such as antibody titers or additional blood work to assess the risk to you or your future pregnancies.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy